Brain Tumor Diagnosis Doesn't Always Mean Cancer
Benign Acoustic Neuromas Often Go Undiagnosed For Years
Apr 21, 2009
Even benign tumors can still cause health issues if they become large enough to press on the brain or on nerves leading to the brain. Fortunately, non-cancerous tumors tend to grow quite slowly, and in some cases are best left untreated as long as they do not cause problems.
The most common type of benign brain tumor is an acoustic neuroma, or AN. It grows deep inside the skull near the brain stem. Although actually located outside of the brain itself, it presses against the brain and nerves. It is non-invasive, meaning it will not penetrate the brain itself, and it will not spread to other locations. Acoustic neuromas are found in all races and, in most cases, they are not hereditary.
Symptoms and Diagnosis of Acoustic Neuromas
Common symptoms of an AN can include sudden vertigo (loss of balance) and constant tinnitis (ringing or other noises in one ear). A large tumor may cause facial twitching, headaches and lack of sensation in parts of the face on the same side as the tumor. These problems are caused by the tumor pressing on cranial nerves that carry signals to and from the brain.
Some patients, especially with a small tumor, may not experience any symptoms at all, and only discover they have an AN when an MRI (Magnetic Resonance Imagery) or CT (computerized tomography) scan done for some other reason, such as a head injury or headaches, reveals the tumor’s existence.
Unilateral hearing loss is a frequent indicator of an AN, and results from the tumor blocking the acoustic nerve, preventing sounds from being carried from the inner ear to the brain. Since the nerve is blocked, a conventional hearing aid is ineffective. An acoustic neuroma often is diagnosed only after a patient develops unexplained and occasionally sudden hearing loss in just one ear.
When a patient sees a doctor about a hearing problem in one ear, the first step is a hearing test. If a hearing loss is confirmed, additional tests will be done, including an MRI to see if there is a tumor, since there could be other reasons for the hearing loss.
Treatment For Acoustic Neuromas
Left untreated, a slow-growing or static AN could actually cause no problems, although an AN that begins to grow could become life-threatening if it becomes too big. Fortunately, there are ways to detect these tumors when they are still very small, and new methods of treatment have become available in the past few years to give both patients and doctors several options.
If an AN is detected, the patient needs to discuss these options with a specialist. The size of the tumor is important. If it is less than 1.5 centimetres, the doctor may recommend a wait-and-see approach, with a follow-up MRI after six months and another every year after that to determine if the tumor is growing or remaining fairly constant.
Some ANs grow very little each year, while others can grow an average of 1.5 mm. They are unpredictable, and can begin growing unexpectedly after remaining virtually unchanged for years. This is why annual MRIs are needed to keep track of the growth.
If treatment is chosen, there are two basic options: physical surgery to cut out the growth or radiation to kill it or at least slow its growth. There are pros and cons to each method. Either way, it is highly unlikely the patient will recover any hearing in that ear. In fact, hearing may continue to deteriorate even after treatment, and some facial paralysis can occur.
The good news is that this type of brain tumor can be treated successfully and will not spread into other parts of the body or invade the brain.
Sources and Useful Links
Acoustic Neuroma Association of Canada (ANAC) offers on-line forums, live lectures and AN information.
The AN Patient Archive Site provides first-hand accounts of diagnosis, treatment and problems associated with AN, all compiled by and for people living with an acoustic neuroma.
Hain, Dr. Timothy. “Acoustic Neuroma” (see link with photo).This site contains many diagrams, MRIs and a long list of links to scientific papers and studies about AN.
(The author was diagnosed with an acoustic neuroma in the fall of 2005 and had successful gamma knife surgery in March 2006.)
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